Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B17/00—Insulators or insulating bodies characterised by their form
  • H01B17/14—Supporting insulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B19/00—Apparatus or processes specially adapted for manufacturing insulators or insulating bodies
  • H01B19/04—Treating the surfaces, e.g. applying coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B7/00—Insulated conductors or cables characterised by their form
  • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
  • H01B7/29—Protection against damage caused by extremes of temperature or by flame
  • H01B7/295—Protection against damage caused by extremes of temperature or by flame using material resistant to flame
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B11/00—Communication cables or conductors
  • H01B11/02—Cables with twisted pairs or quads
  • H01B11/06—Cables with twisted pairs or quads with means for reducing effects of electromagnetic or electrostatic disturbances, e.g. screens

Definitions

• separator spline is an isolator having a four-arm shape, such as a cross ( + -shape), or X- shape, or a, and a flat tape-shape with each twisted pair lying in the space between the arms.
• the separator spline may also take other forms, as discussed further below.
• the purpose of the separator spline is to reduce "cross-talk" between each of the twisted pairs of electrical conductors, especially at high data transmission rates.
• the assembled separator spline and sets of twisted pairs can be covered in a sheath to form the completed
• the current materials of choice for the electrically insulative isolators are fluoropolymers or polyolefins, depending on cable construction and performance
• the invention provides a separator spline which is a non-halogen containing polymer having excellent smoke, flame and toxicity properties.
• the separator spline is formed of a polymeric material having excellent smoke flame and toxicity properties, such as polyetherimide (PEI), a polyetherimide/polysiloxane copolymer, a thermoplastic-elastomer-modified-polyphenylene- ether blend and combinations thereof.
• the separator spline is formed of a reduced density material, such as foamed polyetherimide (PEI), a foamed polyetherimide/polysiloxane copolymer, a foamed thermoplastic-elastomer-modified-polyphenylene-ether blend, and combinations thereof.
• foamed separator spline can be manufactured in indefinite lengths of up to 5000 meters and longer by continuous extrusion of a composition comprising polyetherimide (PEI), a polyetherimide/polysiloxane copolymer, a thermoplastic - elastomer-modified-polyphenylene-ether blend and combinations thereof, with a blowing agent, and optionally, a nucleating agent.
• PEI polyetherimide
• polyetherimide/polysiloxane copolymer a thermoplastic - elastomer-modified-polyphenylene-ether blend and combinations thereof
• a blowing agent and optionally, a nucleating agent
• an indefinite length, foamed separator spline can be manufactured by feeding preformed pellets of polyetherimide (PEI), a
• polyetherimide/polysiloxane copolymer a thermoplastic-elastomer-modified-polyphenylene- ether blend and combinations thereof, with a blowing agent, and optionally, a nucleating agent, into a single screw extruder with a cross ( + -shape) or "X"-shaped die to produce foamed extrudate, which can be drawn down, in a profile extrusion process.
• the foamed separator spline can be combined with two or more twisted pairs, preferably four twisted pairs, of conductors nested in the spaces between the arms of the foamed separator spline , and the foamed isolator and twisted pairs being enclosed in a sheath to provide a lightweight non-halogen containing, data communication cable of low smoke, flame and toxicity properties, excellent in dielectric constant to reduce cross-talk between twisted pairs, suitable for use in high speed data transmission, and of acceptable compressive strength for use as data communication cables and components of data systems.
• FIG. 1 is a pictorial representation of a prior art data communication cable
• FIG. 2 is a schematic representation of an "X" or cross(+)-shaped separator spline according to the invention
• Fig. 3 is a cross-sectional, schematic representation of an alternative shape for the separator spline of the present invention in the form of a rod;
• Fig. 4 is a cross-sectional, schematic representation of a further alternative shape for the separator spline according to the present invention in the form of a star;
• FIG. 5 is a cross-sectional, schematic representation of a further alternative shape for the separator spline according to the present invention in the form of a tube;
• Fig. 6 is a cross-sectional, schematic representation of a further alternative shape for the separator spline according to the present invention in the form of a flat rectangular shape.
• a prior art data communication cable 10 is formed of a fluoropolymer separator spline 12 into which four twisted pairs 13, 14, 15 and 16 of conductors are nested.
• a sheath 18 surrounds the separator spline 12 and twisted pairs 13, 14, 15 and 16 to complete the communication cable 10.
• Each conductor 20 of the twisted pair may be independently covered in an electrically insulated manner.
• a polyolefin can be used as the material for separator spline 12.
• halogenated compounds may be environmentally harmful.
• Polyolefins present smoke, flame and toxicity hazards, especially in the electrical environment.
• PEI can replace halogenated materials for improved smoke, flame and toxicity (SFT) properties meeting, or exceeding, regulatory requirements for data communications cable, e.g., the Underwriter's Laboratory Standard UL-910 Plenum Test, or NFPA 262.
• SFT smoke, flame and toxicity
• NFPA 262 regulatory requirements for data communications cable
• the dielectric constant of the PEI could be improve by introducing a chemical or physical blowing agent into the PEI to reduce its density and improve its dielectric constant. Density reduction of as little as 3% demonstrated
• halogen-free when used to describe a polymer, the term means that the polymer does not contain halogen atoms in the polymeric chain and no compounds added to the formulation which contain non-trace levels of halogen.
• the present inventors have discovered that density reduction of from about 3% to about 62% represents the operative range with density reduction of from about 3% to about 55% being preferred. It is to be understood that dielectric performance of the separator spline improves as density decreases.
• the dielectric constant of solid (unfoamed) PEI is about 3.15 and the density reductions according to the invention can yield dielectric constants on the order of about 2.0.
• Foaming of the PEI, or other polymers/copolymers or blends, suitable for use in the invention, can be achieved during melt processing into a shape suitable for the separator spline.
• the separator spline 30 according to the invention is formed of a PEI
• ULTEM 1000 commercially available from SABIC Innovative Plastics of Pittsfield, Massachusetts
• a suitable blowing agent is dihydrooxadazinone in a PEI carrier, commercially available as ULTEM FUL-C20, from SABIC Innovative Plastics of Pittsfield, Massachusetts.
• a nucleating agent such as talc, (commercially available as Ultra Talc 609 from Specialty Minerals Inc. of Bethlehem, PA), is included for improved bubble formation.
• the PEI and nucleating agent have been previously processed in a compounding extruder to form pellets, which pellets are the feedstock for the extrusion process forming the separator spline extrudate.
• the nucleating agent can optionally be present, and when present, is preferably present in an amount of about 0.5% by weight, based on the weight of the PEI. In another embodiment, the amount of the nucleating agent can range from about 0.1 to 10% by weight, based on the weight of the PEI When used, the blowing agent is preferably present in an amount of about 0.25% to about 1.0% by weight. In another embodiment, the amount of the blowing agent can range from about 0;05% to about 1.0%, by weight.
• the resultant separator spline can be made from a PEI providing desirable smoke, flame and toxicity performance without halogen-containing materials. Furthermore, because the PEI is foamed during the forming of the separator spline , the presence of bubbles, which have a lower dielectric constant than that the neat resin, improves the dielectric constant of the separator spline over neat PEI to further inhibit cross talk between the twisted pairs, as well as reducing overall part weight without compromising physical properties of the resultant cable and providing a higher compressive strength as compared to fluoropolymers and polyolefins, improving the functionality of the separator spline to hold the conductors apart.
• the separator spline in a preferred form comprises a separator spline having a length ranging from 1 meter to 5000 meters and a cross sectional dimension ranging from 0.1 mm to 5 mm, and a thickness ranging from 0.1 to 5 mm.
• the foamed separator spline exhibits a compressive strength ranging from 15 to less than 124 MPa, preferably a compressive strength of 27 to 84 MPa.
• FIG. 3 illustrates separator spline 32 in the form of a rod having numerous cavities 34, 35, 36 to act as receptacles for a twisted pair.
• Fig. 4 shows the shape of the separator spline 42 as a star with several spaces 44, 45, 46 between the points 47, 48, 49 to accept a twisted pair.
• Fig 5 illustrates a tube 52 having numerous cavities 54, 55, 56 to accept a twisted pair of conductors.
• Fig. 6 illustrates a flat rectangular shape 62 having numerous cavities 64, 65, 66 to accept a twisted pair of conductors.
• flat separator splines according to our invention has no cavities.
• Preferred polyimides include polyetherimides and
• polyetherimide copolymers The polyetherimide can be selected from (i) polyetherimide homopolymers, e.g., polyetherimides, (ii) polyetherimide co-polymers, e.g., polyetherimide siloxane, and (iii) combinations thereof.
• Polyetherimides are known polymers and are sold by SABIC Innovative Plastics under the ULTEM®* and SILTEM* brands (Trademark of SABIC Innovative Plastics IP B.V.).
• the polyetherimides are of formula (1):
• a is more than 1, for example 10 to 1,000 or more, or more specifically 10 to 500.
• the group V in formula (1) is a tetravalent linker containing an ether group (a "polyetherimide” as used herein) or a combination of an ether groups and siloxane groups (a "polyetherimide/siloxane”).
• Such linkers include but are not limited to: (a) substituted or unsubstituted, saturated, unsaturated or aromatic monocyclic and polycyclic groups having 5 to 50 carbon atoms, optionally substituted with ether groups, siloxane groups, or a combination of ether groups and siloxane groups; and (b) substituted or unsubstituted, linear or branched, saturated or unsaturated alkyl groups having 1 to 30 carbon atoms and optionally substituted with ether groups or a combination of ether groups, siloxane groups; or combinations comprising at least one of the foregoing.
• Suitable additional substitutions include, but are not limited to, ethers, amides, esters, and combinations comprising at least one of the foregoing.
• the R group in formula (1) includes but is not limited to substituted or unsubstituted divalent organic groups such as: (a) aromatic hydrocarbon groups having 6 to 20 carbon atoms and derivatives thereof; (b) straight or branched chain alkylene groups having 2 to 20 carbon atoms; (c) cycloalkylene groups having 3 to 20 carbon atoms, or (d) divalent groups of formula (2)
• Q 1 includes but is not limited to a divalent moiety such as -0-, -S-, -C(O)-, -S0 2 -, - SO-, -C y H2y- (y being an integer from 1 to 5), and derivatives thereof.
• linkers V include but are not limited to tetravalent aromatic groups of formula (3):
• W is a divalent moiety including -0-, -S0 2 -, or a group of the formula -0-Z-O- wherein the divalent bonds of the -O- or the -0-Z-O- group are in the 3,3', 3,4', 4,3', or the 4,4' positions, and wherein Z includes, but is not limited, to divalent groups of formulas (4):
• Q includes, but is not limited to a divalent moiety including -0-, -S-, -C(O),
• the polyetherimide comprise more than 1, specifically 10 to 1,000, or more specifically, 10 to 500 structural units, of formula (5):
• T is -O- or a group of the formula -0-Z-O- wherein the divalent bonds of the -O- or the -0-Z-O- group are in the 3,3', 3,4', 4,3', or the 4,4' positions;
• Z is a divalent group of formula (3) as defined above; and
• R is a divalent group of formula (2) as defined above.
• the polyetherimides can be synthesized by the reaction of the bis(phthalimide) (8) with an alkali metal salt of a dihydroxy substituted aromatic hydrocarbon of the formula HO-V-OH wherein V is as described above, in the presence or absence of phase transfer catalyst.
• Suitable phase transfer catalysts are disclosed in U.S. Patent No. 5,229,482, incorporated herein by reference.
• the dihydroxy substituted aromatic hydrocarbon a bisphenol such as bisphenol A, or a combination of an alkali metal salt of a bisphenol and an alkali metal salt of another dihydroxy substituted aromatic hydrocarbon can be used.
• the polyetherimide comprises structural units of formula (5) wherein each R is independently p-phenylene or m-phenylene or a mixture comprising at least one of the foregoing; and T is group of the formula -0-Z-O- wherein the divalent bonds of the -0-Z-O- group are in the 3,3' positions, and Z is 2,2-diphenylenepropane group (a bisphenol A group).
• the silicon polyetherimide can be any silicon-containing polyetherimide, which when used in accordance with the invention, enables the composition to exhibit a useful combination of improved flame retardancy, low smoke, and high impact strength properties, such that the compositions can pass the ASTM E 162 Standard Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source.
• Siloxane polyimide copolymers are a specific silicon polyetherimide that may be used in the blends of this invention. Examples of such siloxane polyimides are described in U.S.
• Siloxane polyimides can be prepared by standard methods to make polyimides wherein at least a portion, generally from 5 to 70 wt. , and optionally from 10 to 50 wt. , of the imide is derived from siloxane containing diamines, siloxane containing dianhydrides or chemical equivalents thereof.
• siloxane polyimides include SILTEM*s, which can be obtained from SABIC Innovative Plastics (*Trademark of SABIC Innovative Plastics).
• siloxane polyimide can be prepared by any of the methods known to those skilled in the art, including the is(ether anhydride) of the Formula 6,
• T is a divalent moiety selected from -0-, -S-, -C(O)-, S0 2 -, -SO, a direct linkage, a fused ring linkage, or a group of the formula -0-Z-O- wherein the divalent bonds of the -T- or the -0-Z-O- group are in the 3,3', 3,4', 4,3', or the 4,4' positions, and wherein Z includes, but is not limited, (a) aromatic hydrocarbon radicals having about 6 to about 36 carbon atoms and halogenated derivatives thereof including perfluoroalkylene groups; (b) straight or branched chain alkylene radicals having about 2 to about 24 carbon atoms (c) cycloalkylene radicals having about 3 to about 20 carbon atoms, or (d) divalent radicals of the general
• Q includes but is not limited to a divalent moiety selected from -0-, -S-, -C(O)-, - S0 2 -, -SO-, -Cy by- (y being an integer from 1 to 8), and fluorinated derivatives thereof, including perfluoroalkylene groups, and wherein at least a portion of the reactants, either dianhydride, diamine, or mixtures thereof, contain a siloxane functionality.
• R in Formula 2 includes but is not limited to substituted or unsubstituted divalent organic radicals such as: (a) aromatic hydrocarbon radicals having about 6 to about 36 carbon atoms and halogenated derivatives thereof; (b) straight or branched chain alkylene radicals having about 2 to about 20 carbon atoms; (c) cycloalkylene radicals having about 3 to about 24 carbon atoms, or (d) divalent radicals of the general Formula 8.
• divalent organic radicals such as: (a) aromatic hydrocarbon radicals having about 6 to about 36 carbon atoms and halogenated derivatives thereof; (b) straight or branched chain alkylene radicals having about 2 to about 20 carbon atoms; (c) cycloalkylene radicals having about 3 to about 24 carbon atoms, or (d) divalent radicals of the general Formula 8.
• Suitable diamine compounds are ethylenediamine,
• diamino compounds are aromatic diamines, especially m- and p- phenylenediamine, sulfonyl dianilines, bis aminophenoxy benzenes, bis amino phenoxy sulfones and mixtures comprising at least one of the foregoing diamines.
• aromatic bis anhydrides examples include: 3,3-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride; 4,4'- bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride; 4,4'-bis(3,4- dicarboxyphenoxy)diphenyl sulfide dianhydride; 4,4'-bis(3,4- dicarboxyphenoxy)benzophenone dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride; 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride; 4,4'- bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride; 4,4'-bis(2,3- di
• the polyetherimides include a polyetherimide thermoplastic composition, comprising: (a) a polyetherimide, and (b) a phosphorus-containing stabilizer, in an amount that is effective to increase the melt stability of the polyetherimide, wherein the phosphorus-containing stabilizer exhibits a low volatility such that, as measured by thermogravimetric analysis of an initial amount of a sample of the phosphorus- containing stabilizer, greater than or equal to 10 percent by weight of the initial amount of the sample remains unevaporated upon heating of the sample from room temperature to 300° C. at a heating rate of a 20° C. per minute under an inert atmosphere.
• the phosphorous-containing stabilizer has a formula P-R' a , where R' is independently H, alkyl, alkoxy, aryl, aryloxy, or oxy substituent and a is 3 or 4.
• R' is independently H, alkyl, alkoxy, aryl, aryloxy, or oxy substituent and a is 3 or 4.
• suitable stabilized polyetherimides can be found in U.S. Pat. No. 6,001,957,
• the separator spline comprises an amorphous polymer composition comprising (a) a polyetherimide, and (b) a phosphorus-containing stabilizer, in an amount that is effective to increase the melt stability of the polyetherimide, wherein the phosphorus-containing stabilizer exhibits a low volatility such that, as measured by thermogravimetric analysis of an initial amount of a sample of the phosphorus-containing stabilizer, greater than or equal to 10 percent by weight of the initial amount of the sample remains unevaporated upon heating of the sample from room temperature to 300° C. at a heating rate of a 20° C. per minute under an inert atmosphere.
• the article is made such that the phosphorous-containing stabilizer has a formula P-R a , where R' is independently H, alkyl, alkoxy, aryl, aryloxy, or oxy substituent and a is 3 or 4.
• the polyimide siloxanes can also be prepared in a manner similar to that used for polyimides, except that a portion, or all, of the organic diamine reactant is replaced by an amine-terminated organosiloxane, for example of the Formula 9 wherein g is an integer from 1 to about 100, optionally from about 5 to about 50, and R' is an aryl, alkyl or aryl alky group of from 2 to 20 carbon atoms.
• Some polyimide siloxanes may be formed by reaction of an organic diamine, or mixture of diamines, and the amine-terminated organosiloxane of Formula 9, and one or more dianhydrides.
• the diamino components may be physically mixed prior to reaction with the bis-anhydride(s), thus forming a substantially random copolymer.
• block or alternating copolymers may be formed by selective reaction of 4 with dianhydrides to make polyimide blocks that are subsequently reacted together.
• the siloxane used to prepare the polyimide copolymer may have anhydride rather than amine functional end groups, for example as described in US Patent 4,404,350, the entire disclosure of which is herein incorporated by reference.
• siloxane polyimide copolymer can be of Formula
• n is from 5 to about 100 and Ar is an aryl or alkyl aryl group of from 6 to 36 carbons.
• the diamine component of the siloxane polyetherimide copolymers may contain from about 5 to 70 wt.% of the amine-terminated organosiloxane of Formula 9 and from about 30 to 95 wt.% of the organic diamine of Formula 7.
• the siloxane component contains from about 25 to about 40 wt. % of the amine or anhydride terminated organosiloxane.
• the siloxane polyimides can be siloxane polyetherimides which contain aryl ether linkages that can be derived by polymerization of dianhydrides and/or diamines wherein at least a portion of the dianhydride or the diamine contains an aryl ether linkage.
• both the diamine and dianhydride will contain an aryl ether linkage and at least a portion of the diamine or dianhydride will contain siloxane functionality, for example as described above.
• the aryl ether linkage can be derived from dianhydrides such as bisphenol A diphthalic anhydride, biphenol diphthalic anhydride, oxy diphthalic anhydride or mixtures thereof.
• the aryl ether linkages can be derived from at least one diamine containing aryl ether linkages, for example, diamino diphenyl ethers, bis amino phenoxy benzenes, bis amino phenoxy phenyl sulfones or mixtures thereof.
• Either the diamine or dianhydride may have aryl ether linkages or in some instances both monomers may contain aryl ether linkages.
• the silicone polyetherimide can have from about 5 to about 50, from about 10 to about 40, or from about 20 to about 30 percent by weight dimethyl siloxane units.
• the silicone polyetherimide can have less than about 100, less than about 75, or from 10 to about 50 ppm amine end groups;
• the silicone polyetherimide can have a weight average molecular weight from about 5,000 to about 70,000, from about 10,000 to about 60,000, or from about 20,000 to about 50,000 Daltons.
• the articles can be made by any suitable method.
• the separator splines can be made by extruding.
• the separator splines can be made by a method for making an article comprising extruding, injection molding, compressing molding, machining, and/or film pressing.
• separator splines can be made by additive manufacturing techniques.
• our separator spline can be made by any suitable process that uses additive manufacturing strategies.
• our invention includes a method for building a three-dimensional separator spline in an extrusion-based digital manufacturing system, the method comprising: providing a consumable filament of the polymeric material to the extrusion-based digital manufacturing system, the consumable filament having a length, an exterior surface, and a plurality of tracks along at least a portion of the length, wherein the plurality of tracks provide a fractal dimensionality for at least a portion of the exterior surface that is greater than two for a suitable length scale, e.g., a length scale between 0.01 millimeters and 1.0 millimeter; engaging teeth of a rotatable drive mechanism retained by the extrusion-based digital manufacturing system with the plurality of tracks of the consumable filament; feeding successive portions of the consumable filament with the rotatable drive mechanism to a liquefier retained by the
• the consumable filament can be made by any suitable geometry.
• the consumable filament has a substantially cylindrical geometry with an average diameter ranging from about 1.143 millimeters to about 2.54 millimeters.
• the consumable filament has a substantially rectangular cross-sectional profile.
• the plurality of tracks can be selected from rectangular tracks, parabolic tracks, worm-type tracks, corrugated tracks, textured tracks, impressed file-type tracks, herringbone-type tracks, sprocket tracks, edge-facing tracks, staggered tracks, and combinations thereof.
• our invention includes an embodiment in which the separator spline is made in an extrusion-based digital manufacturing system, the method comprising:
• the consumable filament having a length, an exterior surface, and a plurality of tracks along at least a portion of the length, wherein the plurality of tracks provide a fractal dimensionality for at least a portion of the exterior surface that is greater than two for a length scale between 0.01 millimeters and 1.0 millimeter; engaging teeth of a rotatable drive mechanism retained by the extrusion-based digital manufacturing system with the plurality of tracks of the consumable filament; feeding successive portions of the consumable filament with the rotatable drive mechanism to a liquefier retained by the extrusion-based digital manufacturing system, wherein successive teeth of the rotatable drive mechanism are continuously engaged with successive tracks of the plurality of tracks while feeding the successive portions of the consumable filament; melting the consumable filament in the liquefier to provide a melted consumable material; extruding the melted consumable material from the liquefier; and depositing the extruded consumable material
• ULTEM 1000 was combined with 0.5% talc by weight using a twin screw extruder and standard polyetherimide compounding conditions to produce a compound used in subsequent extrusion trials to produce foamed parts.
• a blowing agent (ULTEM FUL-C20) (with 0.5 wt% talc) in various amounts was used in preparing the foamed separator spline s according to the invention.
• PEI polyetherimide
• ULTEM 1000 polyetherimide
• air bubbles a neat resin
• the PEI was fed to the Akron single screw extruder under the conditions specified above to obtain an "+"-shaped extrudate having a relative linear density of 100%, an apparent specific gravity of 1.27 and a density reduction of 0%.
• the weight of a 1 meter length of extrudate was 4.6669 gram. Its properties are as set forth in Table 1.
• Examples 1-5 demonstrate the ability to produce a reduced density part from PEI that could function as a separator spline in a cable construction. With blowing agent loadings of 0.38% and 0.5%, density reductions of 21% and 56% respectively were achieved. Parts were produced which met targeted dimensions for the +-shape cross-section. One skilled in the art of profile extrusion die design and processing would be able to optimize equipment and process conditions to produce other specified dimensions.
• separator splines having a +- shape or an X-shape, and a flat tape-shape to separate each of four twisted pairs of conductors
• isolators separator splines
• the extruder was operated with a temperature profile and screw speed as shown in Table 2. The extruded strand of material was allowed to collect on the floor below the die.
• Table 2 shows results from several extrusion runs with different chemical blowing agents added to PEI and extruded.
• ULTEM 1000 was combined with 0.5% talc by weight using a twin screw extruder and standard polyetherimide compounding conditions to produce a compound used in subsequent extrusion trials to produce foamed parts.
• the extruder was operated with a temperature profile and screw speed as shown Table 3. The extruded strand of material was allowed to collect on the floor below the die.
• Table 3 shows results from extrusion runs with different chemical blowing agents added to a PEI/talc compound and extruded.
• Example 8 The purpose of Example 8 is to produce foamed parts in an extrusion process using a polyetherimide/siloxane copolymer (SILTEM* brand) with a chemical blowing agent.
• SILTEM* brand polyetherimide/siloxane copolymer
• Table D The materials in Table D were used. Table D.
• the extruder was operated with a temperature profile and screw speed as shown in Table 4. The extruded strand of material was allowed to collect on the floor below the die.
• polyetherimide/siloxane copolymer at a level of 2.0% by weight and passed through the extruder to produce a strand of foamed material.
• Table 4 shows results from extrusion runs with polyetherimide and with a polyetherimide/siloxane copolymer plus chemical blowing agent.
• the separator spline was made in an extrusion-based digital manufacturing system as follows.
• the consumable filament had a length, an exterior surface, and a plurality of tracks along at least a portion of the length, such that the plurality of tracks provided a fractal dimensionality for at least a portion of the exterior surface that is greater than two for a length scale between 0.01 millimeters and 1.0 millimeter.
• the teeth of a rotatable drive mechanism retained by the extrusion-based digital manufacturing system engaged with a rotatable drive mechanism with the plurality of tracks of the consumable filament. Portions of the consumable filament were fed successively with the rotatable drive mechanism to a liquefier retained by the extrusion-based digital manufacturing system.
• Successive teeth of the rotatable drive mechanism were continuously engaged with successive tracks of the plurality of tracks while feeding the successive portions of the consumable filament.
• the consumable filament melted in the liquefier to provide a melted consumable material.
• the melted consumable material from the liquefier was extruded and the extruded consumable material was deposited in a layer-by-layer manner to form the separator spline.
• Example 9 illustrates that separator spline parts can be fabricated using an additive manufacturing process.
• Our results show that additive manufacturing processes make articles having reduced density, as compared with separator splines that are solid and made from ULTEM 9085 and that have the same dimensions as those made from the additive manufacturing process.
• the expected weight of a solid part with the described dimensions fabricated with ULTEM 9085, for instance, is 1.43 g.
• the separator splines made by additive manufacturing represented a density reduction ranging from 16% to 28%. No blowing agent was used in this process so the density reduction is due to the open lattice structure produced as material is placed by the additive manufacturing equipment.
• UL-910 Plenum Test is as follows.
• a plenum is defined as any space used as part of an air-handling system. This includes heating/air- conditioning ducts and air returns, which frequently include the space between suspended ceilings and the floor above in modern office buildings.
• the National Electric Code (NEC) requires that "exposed cables (those not in conduit) in plenums be listed as having adequate fire-resistant and low-smoke producing characteristics "
• Smoke is measured by a photocell installed in the exhaust duct.
• cables must have a flame spread of less than 5 feet beyond the end of the 4 1/2 foot ignition flame, a peak optical density of 0.5 maximum (33% light transmission) and a maximum average optical density of 0.15 (70% light transmission).
• an article comprising a foamed, polymeric, separator spline shaped to isolate at least one twisted pair of conductors, optionally wherein the foamed separator spline has a reduced density as compared to a non-foamed solid, separator spline; optionally, wherein the foamed polymeric separator spline is one selected from a foamed polyetherimide (PEI), a foamed polyetherimide/polysiloxane copolymer, a foamed thermoplastic-elastomer-modified-polyphenylene-ether blend, and combinations thereof optionally wherein the separator spline has a length ranging from 1 meter to 5000 meters and a cross sectional dimension ranging from 0.1 mm to 5 mm, and a thickness ranging from 0.1 to 5 mm; optionally wherein the shape of the separator spline is selected from one of the following shapes: (i) a foamed polyetherimide (PEI
• a cable comprising the separator spline of any one of the foregoing embodiments, and a plurality of the twisted conductor pairs encased in a sheath, optionally wherein the cable meets or exceeds at least one of UL-910 Plenum Test and NFPA 262; optionally wherein the cable is a data communication cable and the plurality of twisted conductor pairs is equal to four; optionally wherein the sheath also comprises one selected from the group consisting of a foamed polyetherimide (PEI), a foamed
• the foamed separator spline has a compressive strength ranging from 15 to less than 124 MPa, specifically a compressive strength of 27 to 84 MPa; optionally wherein the dielectric constant of the separator spline material is from about 2.0 to less than 3.15; optionally wherein the separator spline has a shape selected from +-shape, an X-shape, and a flat tape- shape, for example wherein one twisted pair of conductors is present in each of the arms of the + and the X.
• an article comprises a halogen-free separator spline for isolating at least two twisted pair of communication conductors to reduce cross-talk between the conductors, the article comprising: two twisted pairs of communication conductors, a foamed, halogen-free separator spline, the separator spline being interposed between the two pairs of communication conductors, the separator spline comprising a foamed polyetherimide (PEI) or a polyetherimide/siloxane copolymer, wherein the foam reduces the density, as compared to a corresponding non-foamed polymer, in the range of about 3% to about 55%; optionally further comprising a sheath covering the separator spline and the communication conductors.
• PEI polyetherimide
• a sheath covering the separator spline and the communication conductors.
• communication cable comprising at least two twisted pairs of communication conductors, separated by a halogen-free, foamed polymeric separator spline, the twisted pairs and spline being sheathed by an outer covering, optionally wherein the at least two twisted pairs range from two to sixteen twisted pairs; optionally wherein the separator spline has a shape selected from +-shape, an X-shape, and a flat tape-shape, for example wherein one twisted pair of conductors is present in each of the arms of the + and the X.
• a communication cable comprises a plurality of twisted conductor pairs, the conductor pairs being separated by a separator spline, wherein the separator spline has improved smoke, flame, and reduced toxicity properties; wherein the separator spline comprises a melt processed, foamed, polyetherimide (PEI) component selected from the group of polyetherimide homopolymers, polyetherimide copolymers, and combinations thereof, the separator spline having a reduced density, as compared to non- foamed PEI, of from about 3% to about 55%, optionally wherein the polyetherimide copolymercomprises a polyetherimide/polysiloxane copolymer; optionally wherein the dielectric constant of the separator spline material is from about 2.0 to less than 3.15;
• PEI polyetherimide
• the separator spline has a shape selected from +-shape, an X-shape, and a flat tape-shape, for example wherein one twisted pair of conductors is present in each of the arms of the + and the X.
• a method for making the article or cable of any one of the foregoing embodiments comprises extruding a composition through a shaped die, the composition comprising (i) a blowing agent, (ii) a thermoplastic polymer selected from the group of polyetherimide (PEI), polyetherimide/polysiloxane copolymer, elastomer- modified- polyphenylene-ether blend, and combinations thereof, and optionally a nucleating agent.
• PEI polyetherimide
• polyetherimide/polysiloxane copolymer elastomer- modified- polyphenylene-ether blend, and combinations thereof
• nucleating agent optionally a nucleating agent
• Another embodiment is the any of the foregoing articles wherein the separator spline is made in an extrusion-based digital manufacturing system, the method comprising: providing a consumable filament of the polymeric material to the extrusion-based digital manufacturing system, the consumable filament having a length, an exterior surface, and a plurality of tracks along at least a portion of the length, wherein the plurality of tracks provide a fractal dimensionality for at least a portion of the exterior surface that is greater than two for a length scale between 0.01 millimeters and 1.0 millimeter; engaging teeth of a rotatable drive mechanism retained by the extrusion-based digital manufacturing system with the plurality of tracks of the consumable filament; feeding successive portions of the consumable filament with the rotatable drive mechanism to a liquefier retained by the extrusion-based digital manufacturing system, wherein successive teeth of the rotatable drive mechanism are continuously engaged with successive tracks of the plurality of tracks while feeding the successive portions of the consumable filament; melting the consumable filament in the
• any of the foregoing articles can have the separator spline comprising an amorphous polymer composition comprising (a) a
• a phosphorus-containing stabilizer in an amount that is effective to increase the melt stability of the polyetherimide, wherein the phosphorus-containing stabilizer exhibits a low volatility such that, as measured by thermogravimetric analysis of an initial amount of a sample of the phosphorus-containing stabilizer, greater than or equal to 10 percent by weight of the initial amount of the sample remains unevaporated upon heating of the sample from room temperature to 300° C. at a heating rate of a 20° C.
• the phosphorous-containing stabilizer has a formula P-R' a , where R' is independently H, alkyl, alkoxy, aryl, aryloxy, or oxy substituent and a is 3 or 4.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
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• 2013
  • 2013-03-15 US US13/843,208 patent/US20140069687A1/en not_active Abandoned
  • 2013-09-11 KR KR1020157004503A patent/KR102005284B1/ko active IP Right Grant
  • 2013-09-11 WO PCT/US2013/059203 patent/WO2014043194A1/en unknown
  • 2013-09-11 CN CN201380047301.3A patent/CN104620328A/zh active Pending
  • 2013-09-11 EP EP13771661.9A patent/EP2896054B1/de not_active Not-in-force

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